Best: March–May and September–November (NTB, Annapurna Conservation Area page). December–February: Thorong La (5,416 m) is frequently snowbound and crossing can be impossible or lethal in storms. June–August monsoon: landslides and washed-out trail sections; not a safe window. Even in peak season, snowstorms can hit the pass with little warning.
Hazards
▲Altitude illness (AMS/HACE/HAPE) crossing Thorong La at 5,416 m — the highest point of the circuit; NTB: life-threatening above 2,500 m, limit sleeping-altitude gain to 300–500 m/day
▲Sudden blizzards and whiteout on Thorong La — can occur even in October peak season
▲Cold exposure and wind on the pass; pre-dawn crossing in sub-zero temperatures is standard
▲Monsoon landslides and rockfall on steep gorge sections
Guide is a legal requirement: NTB's Revised TIMS Provision (31 Mar 2023) names the 'Annapurna Circuit Trek' among routes where trekkers must be accompanied by a licensed guide and carry an agency-issued TIMS card (NPR 2,000); no exception found for ACAP, and NTNC-ACAP checkposts require registration along the route. Permits: ACAP entry NPR 3,000 foreigners (NTNC epermit portal; doubled if bought at checkpoints) plus TIMS. Historical context not on the agency pages fetched: the October 2014 blizzard killed 40+ people near Thorong La in peak season — treat the pass as a serious high-altitude objective, not a walk-through.
Verified 2026-08-23Official source ↗Dept of National Parks & Wildlife Conservation (Nepal)
